Sorghum brewing using sweet potato enzymic flour to increase saccharification

The diastatic activity of three sweet potato varieties was principally due to \-amylase. Substitution of sorghum malt with sweet potato at 20% (w/v) gave a higher activity than an all-sorghum malt. Maltose in the sorghum/potato wort was 50 mg/ml, similar to that in barley malt. The free alpha amino nitrogen of the sorghum/potato worts was lower than that of the all-sorghum malt but was still within the range needed for yeast growth. Incubation of the potato enzymic extract with isolated sorghum endosperm cell walls and viscosity tests demonstrated the presence of (13, 14)--glucanase (limiting in sorghum) in the sweet potato.     

The technology and properties of beer produced from unmalted sorghum or maize grains

Three basic samples of beers were produced: A, B and C. The grit of A and B contained as unmalted adjuncts 15% (plus 10% of saccharose) and 25% of sorghum grains or maize grits, respectively. The reference beer C was produced with barley malt only. The study of the effects of the unmalted adjuncts on the brewing and the quality of beer revealed that: (a) the use of 15 to 20% of maize or 25% of sorghum increased the content of iso-compounds in wort; (b) the combination of maize grit and saccharose improved the colour of the wort and beer; (c) the addition of 25% sorghum extended saccharification time, slowed down both wort and beer filtration and also produced wort of a darker colour and beer with a slightly bitter aftertaste.     

Fungi,Aflatoxins, Fumonisin B<Subscript>l</Subscript> and Zearalenone Contaminating Sorghum-based Traditional Malt,Wort and Beer in Botswana

Brewing and consumption of traditional beer have social–economic significance in most African countries including Botswana. Traditional sorghum malt, wort, and beer samples were collected from three villages around Gaborone, Botswana. Forty-six malt samples were analyzed for fungi on three different media and developing colonies were subcultured for identification. Rhizopus, Fusarium, Mucor, and Aspergillus were the most common genera isolated. Out of the 46 malt samples, 72% contained Rhizopus stolonifer, 63% Fusarium verticillioides (syn. Fusarium moniliforme), and 37% Aspergillus flavus. Although Aspergillus flavus was isolated from malt samples, aflatoxins (B₁, B₂, G₁, and G₂) were not detected in any of the samples analyzed. When the malt, wort, and beer samples were analyzed for fumonisin B_l and zearalenone, fumonisin B₁ was detected in 3 malt samples, with concentrations ranging from 47 to 1316 μg/kg, while zearalenone was detected in 56%, 48% and 48% of the malt, wort and beer samples, respectively. Zearalenone concentration in samples ranged from 102 to 2213 μg/kg in malt, 26 to 285 μg/l in wort and 20 to 201 μg/l, in beer. Zearalenone carry-over from wort to beer ranged from 23 to 403%. Therefore, although aflatoxins and fumonisin B₁ do not appear to be major contaminants, zearalenone is common and could pose a potential problem in traditional beer in Botswana.     

Bioconversion into ethanol of decorticated red sorghum (Sorghum bicolor L. Moench) supplemented with its phenolic extract or spent bran

The effect of extracted phenolics or spent bran added to decorticated red sorghum kernels during fuel ethanol production was studied and compared to maize and whole red and white sorghums. After liquefaction, free amino nitrogen ranged from 65 to 101 mg/l and at the end of saccharification all mashes had approx. 80 g glucose and 2–5 g maltose/100 g meal (dry basis). Saccharified worts were fermented giving 50–90 ml ethanol/l. The lowest fermentation efficiency (76%) was obtained in the white sorghum. Ethanol yields indicate that sorghum bran or its associated phenolics did not significantly affect the efficiency of the sequential steps involved in ethanol production. Red sorghum is a good alternative to maize to produce ethanol and the difference regarding white sorghum and maize was mainly due to endosperm protein structure and composition.     

Optimization of proteolytic activities in malting sorghum

The effects of malting conditions on proteolytic activities in three improved sorghum varieties: ICSV400, SK5912 and KSV8 were studied. Grains were steeped for 45 h using 6 h wet and 3 h dry cycles and germinated for 8 days. Moisture contents and their effects on proteolytic activity were monitored at various intervals using standard methods. Significant positive correlations existed between moisture content and carboxypeptidase and proteinase activities during steeping. Optimum carboxypeptidase and proteinase enzyme activities were consistently recorded in both ICSV400 and SK5912 at the 40th h of steeping while those of KSV8 occurred on the 45th h. This suggests that protein hydrolysis of KSV8 is different from that of ICSV400 and SK5912. Similarly, optimum proteolytic activities occurred in all the sorghum varieties on the 5th day of germination suggesting optimum germination time for optimum protein modification. Variety and steeping time affected both carboxypeptidase and proteinase activities significantly (P<0.001) during germination. Significant positive correlations existed in the sorghum varieties ICSV400 and SK5912 between free amino nitrogen (FAN) contents and carboxypeptidase activities during both steeping and germination. In contrast, variety KSV8 showed no significant correlation between FAN contents and carboxypeptidase activities during either steeping or germination. On the other hand, while there was a highly significant positive correlation between CWS-P development and proteinase activities in all the sorghum varieties during steeping, no such relationship existed during germination.     

Light-Enhanced Uptake of Metabolites in Mesophyll Protoplasts: Evidence for a Novel Pyruvate Transport System

3 ) and sorghum (C₄) leaves for the measurements of osmotic volume change and metabolite uptake. We first investigated whether the silicone oil layer filtering centrifugation method could be applied to the protoplasts. The density of the silicone oil was optimized (ρ =1.026) and 0.5M betaine was chosen as an osmoticum in the protoplast suspending medium. By using [¹⁴C] sorbitol and [¹⁴C] inulin as the marker of the medium carried over into the pellet, protoplast osmotic or internal volume was estimated to be 200–300 μl (mg Chl)⁻¹, with the medium space in the pellet of 8–15 μl (mg Chl)⁻¹. Lowering of the osmotic pressure of the medium induced protoplast swelling as expected. Light also induced swelling. Using this system, we could detect light-enhanced uptake of ascorbate, glutamate and pyruvate in both barley and sorghum protoplasts. Pyruvate uptake was far higher in barley than in sorghum and inhibited by various inhibitors, showed saturation kinetics and, therefore, seemed to be mediated by a translocator protein. Received 10 August 1999/ Accepted in revised form 6 December 1999     

Amylolytic potentials and wort fermenting components of Nigerian sorghums and barley

The diastatic power of four improved Nigerian sorghum cultivars was produced principally by -amylolytic activity, unlike that of Nigerian Proctor barley which came principally from -amylolytic activity. Free amino nitrogen levels and extracts of the sorghums were higher than those of barley when the sorghum was mashed in a modified procedure in which the separated active wort was added to the gelatinized (and cooled) sorghum starch of the mash. The percentage fermentability of the sorghum worts ranged from 76 to 79% for the four cultivars as against 83% for Proctor barley. Maltose in the sorghum worts was about 15 mg/ml compared with 50 mg/ml in the barley wort. Maltotriose in the sorghum worts was 14 to 16 mg/ml while in barley it was 11 mg/ml.     

Changes in water relation parameters under osmotic and salt stresses in maize and sorghum

A relatively drought tolerant cultivar of maize ( Zea mays L. cv. Pioneer 3950) and a drought tolerant line of sorghum ( Sorghum bicolor [L.] Moench cv. ICSV 112) were grown hydroponically for 11 days. Treatments for non-ionic osmotic and salt stresses were started at the 8th day by addition of polyethylene glycol 6000 and NaCl, respectively, at 200 mOsm equivalent concentrations in the presence or absence of 0. 1 μ M abscisic acid. Relative growth rate was depressed by both stress factors, more severely for maize than sorghum. Abscisic acid increased the growth rate and reverted the negative effect of NaCl in maize, while sorghum was only slightly affected. In general, sorghum had higher levels of K⁺ and lower levels of Na⁺ and the K⁺/Na⁺ ratio was further increased by abscisic acid treatment. From the pressure-volume curves, osmotic potential, the water potential at turgor loss point, bulk elastic modulus and the water saturation deficit at initial turgor loss were estimated. Most significantly, sorghum had a higher elastic modulus than maize and it decreased under osmotic treatment, while in maize it increased under NaCl stress. The results suggest that bulk tissue turgor was not limiting growth under these conditions and underscores the possible implications of changes in the elastic condition of the cell walls in stress responses.     

Plant regeneration from embryogenic cell suspension cultures of wild sorghum (Sorghum dimidiatum Stapf.)

A simple and efficient protocol is described for regeneration of wild sorghum (Sorghum dimidiatum) from cell suspension cultures. Fast-growing cell suspensions were established from shoot-meristem-derived callus. Plating of the suspension on Murashige and Skoog agar medium supplemented with 2.5 mg l^–1 2,4-dichlorophenoxyacetic acid (2,4-D) resulted in the formation of embryogenic calli. High-frequency (80%) somatic embryogenesis from small cell clusters (300–400 μm) was observed when the cultures were initially maintained in liquid medium with reduced levels of 2,4-D (0.25 mg l^–1), followed by transfer to regeneration medium. Direct plating of these small clusters on regeneration medium or transfer to liquid regeneration medium containing kinetin and 6-benzylaminopurine resulted in the development of mature somatic embryos and plantlets. The regenerants developed to maturity and were all phenotypically and cytologically normal. Received: 20 May 1998 / Revision received: 1 September 1998 / Accepted: 23 September 1998     

Enhanced germination of barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> L.) using chitooligosaccharide as an elicitor in seed priming to improve malt quality

Objectives

To study enhanced barley germination by chitooligosaccharide as an elicitor for improving the quality of malt.

Results

Barley germination for both radical and leaf sprouts was enhanced when chitooligosaccharide was added to the steeping water in the first steeping cycle. The activities of hydrolases (α-/β-amylase, proteinase and β-glucanase) and antioxidases (superoxide dismutase and catalase) in the resultant malt were increased in a dose-dependent manner when chitooligosaccharide was supplemented in the steeping water. Maximal promotion was at 1 mg chitooligosaccharide/l for α-/β-amylase and proteinase, and at 10 mg/l for β-glucanase, superoxide dismutase and catalase. Malt quality, including free α-amino nitrogen content, Kolbach index, malt extract content, diastatic power, wort viscosity and the ratio of glucose, maltose and maltotriose, was significantly improved by chitooligosaccharide in seed priming at 1 mg/l.

Conclusion

Application of chitooligosaccharide in the steeping water promotes barley germination and improves the quality of malt.

     

Pyramiding QTLs to improve malting quality in barley: gains in phenotype and genetic diversity

The ability of barley (Hordeum vulgare L.) breeders to deliver germplasm that combine elite malt quality characteristics, disease resistances, and important agronomic traits has been greatly enhanced by the use of molecular marker technologies. These technologies facilitate the rapid transfer of desirable traits from diverse, elite, germplasm into locally adapted varieties. This present study sought to obtain an additive genetic effect by combining favourable alleles associated with the malting quality of two elite donor parents (Harrington and Morex) such that the resultant progeny would possess quality superior to either parent. Analysis of genetic diversity, based on whole-genome profiling with 700 DArT markers, showed clear separation of the BC₆F₁-derived doubled haploid lines from existing malting barley germplasm, indicating they represent a distinctly different source population for genetic improvement. Micro-malting quality results of the BC-derived lines showed substantial quality improvements, compared with the recurrent parent. Malt extract levels were increased by 1.5–2.0%, while diastase levels increased from approximately 320 WKE to 400–460 WKE. Similarly, α-amylase levels were increased from 160 units to between 218 and 251 units, and wort viscosities lowered from 1.90 cps to 1.72–1.82 cps. Other quality improvements include increases in β-glucanase levels from 375 to between 447 and 512 units, and reductions in wort β-glucan levels by 30–60%. Whilst the genetic gains compared to the recurrent parent were impressive, quality of the derived lines were largely equivalent to the levels now available in the recently released varieties, Buloke and Flagship. In a few cases, the backcross-derived lines also showed similarities to the original donors, Harrington and Morex, but in none of the cases did quality of these lines exceed those of either Harrington or Morex.     

Partial Purification and N-Terminal Amino Acid Sequencing of a β-1,3-Glucanase from Sorghum Leaves

A protein with an apparent molecular mass of 30 kDa that cross-reacts with barley glucanase antiserum was detected in healthy leaves of sorghum (Sorghum bicolor (L.) Moench). When sorghum leaves were infected with Exserohilum turcicum, the causal agent of leaf blight, the 30-kDa glucanase was substantially induced. The 30-kDa glucanase was partially purified from sorghum leaves using ammonium sulfate fractionation and anion exchange chromatography on DEAE-sephacel. The N-terminal amino acid sequence of the 30-kDa glucanase shows homology to glucanases of maize, barley, bean, soybean, tobacco and pea. The purified 30-kDa glucanase showed antifungal activity against Trichoderma viride.     

Diurnal oscillation of SBE expression in sorghum endosperm

Spatial and temporal expression patterns of the sorghum SBEI, SBEIIA and SBEIIB genes, encoding, respectively, starch branching enzyme (SBE) I, IIA and IIB, in the developing endosperm of sorghum (Sorghum bicolor) were studied. Full-length genomic and cDNA clones for sorghum were cloned, and the SBEIIA cDNA was used together with gene-specific probes for sorghum SBEIIB and SBEI. In contrast to sorghum SBEIIB, which was expressed primarily in endosperm and embryo, SBEIIA was also expressed in vegetative tissues. All three genes shared a similar temporal expression profile during endosperm development, with a maximum activity at 15-24 d after pollination. This differed from barley and maize, in which SBEI gene activity showed a significantly later onset compared to that of SBEIIA and SBEIIB. Expression of the three SBE genes in the sorghum endosperm exhibited a diurnal rhythm during a 24-h cycle.     

Phytotoxicity of pathogenic fungi and their mycotoxins to cereal seedling viability

Aspergillus flavus, Alternaria alternata and Fusarium oxysporum were the pathogenic fungi most reduced cereal (barley, sorghum and wheat) seedlings. The pathogens have the ability to produce aflatoxin B₁ and G₁, diacetoxyscirpenol, kojic acid and tenuazonic acid that reduced seedling viability. The inhibition dose for 50% reduction (LD₅₀) was recorded by aflatoxins at 0.83 mg L^-1 for barley, 1.74 mg L^-1 for wheat and 2.75 mg L^-1 for sorghum. Diacetoxyscirpenol produced its inhibition at 1.26 mg L^-1 for barley, 3.98 mg L^-1 for wheat and 10 mg L^-1 for sorghum. Kojic acid induced 50% inhibition at 63 mg L^-1 for barley, 105 mg L^-1 for wheat and 251 mg L^-1 for sorghum. However, tenuazonic acid was less toxic where the toxicity ranged between 79–550 mg L^-1. The germination inhibition was more pronounced in barley followed by wheat and was negligible in sorghum for all tested mycotoxins. This inhibition was attributed to the reduction in the seedling amylase activity, where amylase was also reduced in the same trend: barley > wheat > sorghum. Grain treated with carboxin-captan and thiophanatemethyl-thiram at 1 g kg^-1 grain increased the seedlings vigour of wheat in sterilized soil by 45 and 22%, barley by 24 and 33% and sorghum by 15 and 30%, respectively. These fungicides also had a positive effect on cereal when the soil was inoculated with A. flavus, A. alternata and F. oxysporum, but the improvement was still below normal. This revised version was published online in June 2006 with corrections to the Cover Date.     

Localization of superoxide dismutase in leaves of C3 and C4 plants

Chloroplasts, mitochondria and cytoplasm, isolated from pea,wheat, maize and sorghum mesophyll protoplasts, contain distinctforms of superoxide dismutase (SOD). In all species evaluated,chloroplasts exhibited a single cyanide-sensitive SOD. Thischloroplastic enzyme was the most anionic SOD observed in wholeleaf and protoplast extracts and constitutes 50–80% ofthe total soluble SOD. Pea and wheat protoplasts had only onecytoplasmic SOD, a cyanide-sensitive form of intermediate mobility;maize and sorghum had two such cytoplasmic enzymes. A singlecyanide-insensitive SOD was present in extracts from both C₃and C₄ tissues and was associated with mitochondria. Although bundle sheath cells of sorghum and maize are knownto be deficient in Photosystem II, there was no apparent differencein SOD between mesophyll and bundle sheath cells. Mesophyllprotoplasts and bundle sheath strands from these C₄ plants containedthe same forms of SOD. Levels of soluble SOD were similar, ona chlorophyll basis, in the two cell types as was distributionof activity among the various forms of the enzyme. (Received May 19, 1980; )     

Preliminary Study of the Enzymolysis of Sorghum and Barley Pentosans and their Levels in Worts

The pentosanase complex of the sorghums, unlike that of barley, does not embody a xylosidase, but as in barley, displays arabinosidase activity. Isolation and purification studies, following elution in a DEAE-SS cellulose column, reveal that unlike in barley the water-soluble pentosans are arabinans. Using a modified Bial's orcinol–HCl method, after dialysis to remove free sugars, polymeric pentosans of barley worts were found to range from 162 mg/100 ml in the unmalted grains to 239 mg/100 ml in the 6 day malts while that of the sorghum over the same period was from 41 to 79 mg/ml.     

Monovalent cation transporters; establishing a link between bioinformatics and physiology

Toxic aluminum (Al) ion is a major constraint to plant growth in acid soils. Aluminum tolerance in wheat (Triticum aestivum L.) is strongly related to the Al-triggered efflux of malate from root apices. A role of the secreted malate has been postulated to be in chelating Al and thus excluding it from root apices (malate hypothesis), but the actual process has yet to be fully elucidated. We measured Al content and root growth during and after Al exposure using seedlings of near-isogenic lines [ET8 (Al tolerant) and ES8 (Al sensitive)] differing in the capacity to induce Al-triggered malate efflux. Aluminum doses that caused 50% root growth inhibition during 24-h exposure to Al in calcium (Ca) solution (0.5 mM CaCl₂, pH 4.5) were 50 μM in ET8 and 5 μM in ES8. Under such conditions, the amount of Al accumulated in root apices was approximately 2-fold higher in ET8 than ES8. Al-treated seedlings were then transferred to the Al-free Ca solution for 24 h. Compared to control roots (no Al pretreatment), root regrowth of Al-treated roots was about 100% in ET8 and about 25% in ES8. The impaired regrowth in ES8 was observed even after 24-h exposure to 2.5 μM Al which had caused only 20% root growth inhibition. The addition of malate (100 μM) during exposure to 50 μM Al in ES8 enhanced root growth 1.6 times and regrowth in Al-free solution 7 times, resulting in similar root growth and regrowth as in ET8. Short-term Al treatments of ES8 for up to 5 h indicated that the Al-caused inhibition of root regrowth started after 1-h exposure to Al. The stimulating effect of malate on root regrowth was observed when malate was present during Al exposure, but not when roots previously exposed to Al were rinsed with malate, although Al accumulation in root apices was similar under these malate treatments. We conclude that the malate secreted from root apices under Al exposure is essential for the apices to commence regrowth in Al-free medium, the trait that is not related to the exclusion of Al from the apices.     

Malting and brewing qualities of some Nigerian rice (Oryza sativa L.) varieties and some thoughts on the assessment of malts from tropical cereals

The maiting qualities of six varieties of Nigerian rice were studied and compared with malts from sorghum and barley. A minimum of seven days was necessary for maximum yield of extract from malted rice. The beer brewed from the six rice malts were similar to each other and to those from sorghum and barley in analytical properties. The appropriateness of using methods designed for assessing barley malt should be re-examined for studying malts from tropical cereals. Meanwhile, it should be sufficient to determine the extract and the nitrogen content of the wort using the European Brewing methods to assess a tropical cereal for mall.

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Résumé Les qualités de maltage de six variétés de riz nigérians ont été étudiées et comparées avec des malts de sorghum et d'orge. Un minimum de 7 jours de maltage est necessaire pour le rendement maximum de l'extrait de riz malté. Les bières brassées à partir de ces six malts de riz étalent samblables entre elles et à celles du sorghum et de l'orge quant à leurs propriétés analytiques. Le caractère approprié de l'emploi de méthodes concues pour évaluer le malt d'orge devrait être réexaminé quand il s'agit d'étudler des malts de ceréales tropicales. Entretemps, pour évaluer le potentiel en malt d'une céréale tropicale, ll devrait être suffisant de déterminer l'extrait EBC et le contenu en azote du moüt, tous deux par la méthode de la Convention Européenne Brassicole.

     

Characterization of 9-fatty acid hydroperoxide lyase-like activity in germinating barley seeds that transforms 9(S)-hydroperoxy-10(E),12(Z)-octadecadienoic acid into 2(E)-nonenal

Previously, we reported that 2(E)-nonenal, having a low flavor threshold (0.1 ppb) and known as the major contributor to a cardboard flavor (stale flavor) in stored beer, is produced by lipoxygenase-1 and a newly found factor named 9-fatty acid hydroperoxide lyase-like (9-HPL-like) activity in malt. To assess the involvement of 9-HPL-like activity in beer staling, we compared the values of the wort nonenal potential, an index for predicting the staleness of beer, with the lipoxygenase and 9-HPL-like activity of 20 commercial malts. There was a significant correlation between the malt 9-HPL-like activity and the values of wort nonenal potential (r=0.53, P<0.05), while the correlation between malt lipoxygenase activity and the wort nonenal potential was statistically insignificant. Analysis of the partially purified 9-HPL-like activity from embryos of germinating barley seeds indicated that 9-HPL-like activity consisted of fatty acid hydroperoxide lyase and 3Z:2E isomerase.     

The effect that nickel,copper, and zinc salts have on seed germination and initial ontogenesis of water parsnip (<Emphasis Type="Italic">Sium latifolium</Emphasis> L.) and wood club-rush (<Emphasis Type="Italic">Scirpus silvaticus</Emphasis> L.)

The effect that nickel, copper, and zinc sulfates have on seed germination and the initial stages of the ontogenesis of water parsnip and wood club-rush has been investigated. Nickel and copper in the concentration range of 250–500 mg/l and zinc at a concentration of 500 mg/l were the most toxic for water parsnip seeds, while, for the wood club-rush seeds, maximum toxicity was observed at Ni and Cu concentrations ranging from 50 to 500 mg/l and at Zn concentrations of 250–500 mg/l. The development of water parsnip seedlings was normal at Ni concentrations of 1–25 mg/l, Cu concentrations of 1–10 mg/l, and Zn concentrations up to 50 mg/l; the development of wood club-rush seedlings was normal at a Ni concentration of 1 mg/l, and Cu and Zn concentrations of 1–25 mg/l. A further increase in the concentration caused photosynthesis suppression, slower growth of the vegetation organs, and their subsequent necrosis. Water parsnip is more resistant to the toxicants.